Process for the preparation of transparencies for use in photoreproduction

ABSTRACT

A process for preparing transparencies useful for further photoreproduction, e.g., in photogravure, lithographic, or offset techniques. These images are prepared by imparting impressions of the background portions of xerographic images on polyethylene film layers juxtaposed therewith. The transfer is effected by subjecting the juxtaposed layers to heat and/or pressure.

O United States Patent 1 1 1111 3,873,666 Lerman 1 1 Mar. 25, 1975 15 1PROCESS FOR THE PREPARATION OF 3.311.692 3/1967 Baird 264/293TRANSPARENCIES FOR USE IN PHOTOREPRODUCTION FOREIGN PATENTS ORAPPLICATIONS 1,168,273 10/1969 United Kingdom 264/293 [75] lnvemoriFrank Lermantcmcllmatltohlo 419,620 1934 United Kingdom 264/293 [73]Assignee: National Distillers and Chemical Corporationv New k PrimaryE.\'uminer-Robert F. White [22] Filed: 11 1972 Assistant lirumi/wrGeneAuvillc Attorney, Agent, or Firm-Allen A. Meyer, Jr. [21] Appl. No:314,059

Relatetl US. Application Data [57] ABSTRACT [63] Contmuation-m-part ofSer. Nos. 63,950. Aug. 14,

1970, abandoned, and Ser. No. 311,173, Dec. 1, A process for preparingtransparencies useful for fur- 1972. Pz1t.No.3.796,571. therphotoreproduction, e.g., in photogravure, lithographic, or offsettechniques. These images are pre- [52] US. Cl. 264/219, 264/293 pared bimparting impressions of the background [51] Int. Cl. 82% 1/02 po tionsof xerographic images on olyethylene film Field of Search 264/293. 219layers juxtaposed therewith. The transfer is effected by subjecting thejuxtaposed layers to heat and/or [56] References Cited pressure,

UNITED STATES PATENTS 2442,4115 6/1948 Fornwalt 264/293 5 Clams DrawmgsPROCESS FOR THE PREPARATION OF TRANSPARENCIES FOR USE INPHOTOREPRODUCTION REFERENCE TO RELATED APPLICATIONS This application isa continuation-in-part of copending application Ser. No. 63,950, filedAug. 14, 1970 and now abandoned entitled Process for the Preparation ofPolyethylene Transparencies for Use in Photoreproduction, and recentlyfiled copending application Ser. No. 311,173, filed Dec. 1, 1972 nowU.S. Pat. No. 3,796,571 entitled Process for the Preparation ofPolyethylene Transparencies for Use in Photoreproduction.

Application Ser. No. 63,950 discloses techniques for the preparation oftransparencies on polyethylene film substrates which are suitable foruse in photoreproduction and which are prepared by (l) the transfer tosuch substrates of fixed polyethylene images, (2) the transfer theretoof textured impressions of the non-imaged portions of an original, or(3) the transfer of a releasable layer having a suitable image formedtherein. Each such technique is incorporated by reference herein. Theaforesaid recently filed copending application more fully describes andclaims the first such technique. This application more full describesand claims the second such technique.

BACKGROUND OF THE INVENTION This invention relates to a process for thepreparation of transparencies from xerographic images, whichtransparencies may thereafter be utilized as masters in photogravure,lithographic or offset-printing opera tions.

As used herein, the term transparency is intended to refer to an imagesuitable for photoreproduction and incorporating image elements or areasof varying densities, on or in a light-transmissive (includingtranslucent) substrate.

In many photoreproduction processes, a positive or negative transparencybearing the image to be reproduced is required. In conventional blackand white photographic printing, prints are made from negativetransparencies, the black areas on the print representing thesubstantially light-transmissive areas of the transparency, intermediatetones representing intermediate densities of the transparency, and thewhite areas on the print corresponding to high densities of thetransparency through which virtually no light passes. Thermographicduplication processes may also employ transparencies as originals, andrely for differentiation of the image-defining areas on the relativeproportions of heat radiation transmitted through the transparency.Photogravure, photolithographic, and photo-offset processes formprinting plates for use in gravure, lithographic and offset-printing byexposing a photosensitive surface through a transparency, and thentreating the surface so as to etch, dissolve or otherwise remove orchemically modify the surface in accordance with the light-inducedchanges created therein by the exposure. The varying relief or intaglio,or oleophilic and hydrophilic, areas of the plates thus produced arecapable, upon printing, of duplicating the image on the originaltransparency.

All the preceding photoreproduction processes require an originaltransparency which may be produced photographically. In many cases,however, the material to be duplicated is in the form ofa print, designor decoration in or on an opaque substrate, such as paper, metal, fabricor plastic. Duplication of such an original photographically requiresthat a negative be taken by a camera, the image developed, and the filmprocessed, all of which is time-consuming, and requires cumbersomeequipment.

Duplication procedures are also available which are capable of preparingreproductions of prints, decorations, designs or other images on asubstrate by electrostatic (xerographic) or thermostatic (thermographic)printing. These procedures, however, generally produce a copy on anopaque substrate, which is not suitable for use in reproductionprocesses requiring an original transparency.

Procedures have also been described in the patent literature for formingtransparencies by transfer from originals produced xerographically. Suchtechniques are disclosed, for example, in Carlson U.S. Pat. No.2,990,278 granted June 27, 1961, and Mayer U.S. Pat. No. 3,275,436granted Sept. 27, 1966. The techniques described in the Mayer patent maybe carried out employing polyethylene-coated transfer sheets such asdescribed in Van Dorn U.S. Pat. No. 2,855,324 granted Oct. 7, 1958.

The Carlson, Mayer and Van Dorn patents disclose the xerographicformation of an electrostatic powder image, the subsequent transfer ofsuch image to a transfer layer and, optionally, the application of anadditional material to the non-image portions of the transfer layer.Carlson teaches that the transfer layer is preferably of such acomposition that it does not mechanically bond to the electrostaticpowder image but rather forms only an intermediate support for the imageprior to transfer to a third, and final, substrate therefor. Mayer, onthe other hand, discloses that the transfer layer many adhesivelyreceive the electrostatic powder image and that an additional filmmaterial may thereafter be adhered to such layer in the non-imageportions defined by the electrostatic powder image thereon. Van Dorndescribes the use of, for example, a polyethylene-coated transfer layerand indicates that, alternatively, the electrostatic powder imagetransferred to such layer may be heat fixed thereon.

Each of the preceding techniques is directed to the application of anunfixed (impermanent) electrostatic powder image layer, which may befollowed by further manipulation, e.g., by transfer to yet anotherreceiving layer Carlson, or by the application of a coating to thenon-imaged portions thereof Mayer, prior to fixing the final image. Asacknowledged by Carlson, such manipulations may result in smudgingand/0r offsetting of the electrostatic powder image during the transferoperation as well as in any subsequent manipulations thereof. Theclarity of the final image desired for photoreproductive purposes maythus be substantially impaired.

In the aforesaid recently filed copending application, a process isdescribed and claimed for effecting the formation of a transparency,suitable for use in further photoreproduction, by the transfer of afixed polyethylene image formed, for example, xerographically. It is aprincipal object of the present invention to provide a furtherrelatively simple and yet precise technique for effecting the formationof transparencies from xerographic originals which, like that describedin the said recently filed copending application, is not subject toimage smudging and/or offsetting during use, and provides clear andwell-defined transparencies which are quite suitable for subsequentphotoreproduction.

SUMMARY OF THE INVENTION In accordance with the present invention, aprocess is provided for the preparation of transparencies suitable foruse in photoreproduction, which comprises providing a rough, highlytextured substrate having a smooth non-olefinic xerographic toner,pigment or ink image formed thereon, contacting the substrate with apolyethylene film, and successively heating and cooling the juxtaposedlayers to form and fix textured impressions of the non-imaged areas ofthe substrate in the film. Finally, the polyethylene film is strippedfrom the original substrate a fixed negative transparency (negative withrespect to the image on the original substrate) suitable for use inphotoreproduction thereby being formed on the film.

By producing the initial xerographic image on a rough highly texturedsubstrate, and forming such image in conventional manner utilizing anon-olefinic xerographic toner, pigment or ink, an orginal is providedwhich may readily be utilized in accordance with the present inventionto effect the formation of a polyethylene transparency representingsolely the textured, non-imaged portions of the original. Thus, when thepolyethylene film is placed in contact with the imaged substrate, andthe juxtaposed layers are subjected to successive heating and cooling,an impression of the rough-textured background areas of the original isimparted to the film without, however, anytransfer of the smooth,non-olefinic imaged areas to the film. In this manner a reversal imageis produced which accurately reproduces the textured background providedby the original substrate. Moreover, since no toner, pigment or ink istransferred in the operation, the transparency produced is not subjectto smudging or offsetting and is, therefore, quite suitable forsubsequent photoreproduction.

PREFERRED EMBODIMENTS OF THE INVENTION As indicated hereinabove, anysuitable rough, highly textured substrate may be used in the practice ofthe present invention. Substrates so useful may comprise paper; wood;metal, such as stainless steel, aluminum, chromium'plated steel,nickel-plated steel or cadmiumplated steel; stone; fabrics, both wovenand nonwoven, made of natural or synthetic fibrous material, or blendsthereof; leather; ceramics and porcelain; glass; and opaque oftranslucent plastic materials such as nylon, Teflon(polytetrafluoroethylene), polycarbonates, polystyrene; syntheticrubbers or other elastomeric materials; or cellophane or regeneratedcellulose. By appropriate choice of the textured substrate any desiredesthetic effect may be obtained. For example, decorative woods, e.g.,pine, birch or teak, having designs imprinted thereon may be utilized inthe present process to provide transparencies exhibiting both theimprint and the texture of the original substrate.

The xerographic image applied to the substrate may be formed in anymanner, and utilizing any materials, known to be useful for such purposein the xerographic art. Apart from the electrostatic characteristicsnecessary for such materials, they must provide a smooth surface whichdoes not adhere to the polyethylene film when juxtaposed therewith andsuccessively heated and cooled in accordance with this process.Xerographic toners so useful include various types of nonpolyolefins,e.g., copolymers of styrene and acrylic acid esters, or polyacrylatesper se. Other toners, or inks and pigments similarly used for theformation of xerographic images may, alternatively, be utilized,provided that they meet the additional requirement noted hereinabove.

The xerographic image thus formed is applied to the substrate and fixedin conventional manner. The resulting fixed, non-smudging image issmooth and nonadherent to polyethylene films and is, therefore, quitesuitable for use in the present process.

The polyethylene film to which a reversed image of the xerographicoriginal is imparted may be of any suitable grade or thickness. The useof films having gauges of from about 1 to 5 mils and prepared fromresins having densities varying from about 0.913 to 0.96 is particularlysuitable. Any polyethylene film materials may, however, be utilized solong as, upon juxtaposition with the original image and the applicationof heat and/or pressure thereto, the film material is softened andreceives an impression of the textured background areas of the originaltherein.

In forming the impression it is desirable to press the initial image andthe polyethylene impression or carrier film together at temperatures offrom about to C. and with the application of pressures which maysuitably vary from about 2 to 50 psig. Such heat and/or pressure may beapplied in any suitable manner, e.g., manually, or by pressing the samebetween suitable platens or pressure rolls. When the image and filmlayers are thus juxtaposed they may be sandwiched between a pair ofblock-resistant film layers constituted, for example, of Mylar polyesterfilm to facilitate the impression operation without blocking.

The juxatposed layers are thereafter cooled to temperatures of fromabout 90 to 25C., preferably within about 30 seconds of the initialapplication of heat and- /or pressure, to harden the film and therebyfix the impression of the textured background areas of the originaltherein. The two layers are thereafter stripped apart, leaving atextured reversal image permanently formed in the transparentpolyethylene impression or carrier film and thereby providing the finaltransparency suitable for use in photoreproduction.

If desired, the contrast of the transparency thus produced may beincreased by the addition of an opacifying agent, e.g., a suitablepigment or ink, which adheres preferentially to the textured portions ofthe transparencies formed as aforesaid.

The polyethylene film may, if desired, be laminated to a furthertransparent carrier film whereby to sandwich the textured image betweenthe two films and thus protect it from damage during further use. Thesecond carrier film may be bonded to the completed transparency in anydesired manner.

The following example illustrates one preferred embodiment of theprocess of the present invention. It will be understood that thetechniques described therein are illustrative only, and should not beconstrued in a limiting sense.

EXAMPLE A copy of a printed black and white magazine page was reproducedby an electrostatic copier, forming a fixed image of a copolymer ofstyrene-acrylic ester toner on a standard, uncoated bond paper having ahighly matted texture. The image surface of the paper copy was placed incontact with a thin polyethylene film, the resulting sandwich was heatedand then cooled, and the film was thereafter carefully stripped from thepaper.

No transfer of the fused toner from the paper to the polyethylene filmoccurred. However, the texture of the paper was impressed on the filmresulting in the formation of translucent areas in the filmcorresponding to the non-imaged portions of the original copy. Theportions of the film corresponding to the black printing on the paperremained transparent, due to the smooth surface of the fused toner onthe paper. Thus, a reversal image of the paper copy was formed in thepolyethylene film, having transparent lettering formed on a translucentbackground and being quite suitable for use as a transparency forfurther photoreproduction. Use of the highly matted transparent paper asthe substrate for the original copy was found important to facilitateimparting a relatively opaque texture to the polyethylene filmcontrasting with the transparent lettering corresponding to the printedmatter in the original copy.

Various changes may be made in the preferred embodiment describedhereinabove without departing from the scope of the present invention.Accordingly, the preceding description should be interpreted asillustrative only and not in a limiting sense.

I claim:

1. A process for the preparation of transparencies for use inphotoreproduction, which comprises:

a. providing a rough, highly textured substrate; applying to thesubstrate a smooth non-olefinic image constituted from one of the groupconsisting of fused xerographic toners, pigments and inks;

b. contacting the imaged side of said substrate with a polyethylenefilm;

c. heating the juxtaposed image and film layers to a temperaturesufficient to soften the polyethylene film and thereby form texturedimpressions of the non-imaged areas of said substrate therein;

(1. cooling the juxtaposed layers to fix the textured impressions insaid film; and

e. stripping the thus imaged polyethylene film from said substrate toform a fixed transparency suitable for further use in photoreproduction.

2. The process of claim 1, wherein the original image formed on saidsubstrate is constituted on a copolymer of a styrene-acrylic ester orpolyacrylate-type xerographic toner.

3. The process of claim 1, wherein said substrate is paper.

4. The process of claim 1, wherein said substrate and the polyethylenefilm layer are placed in contact by sandwiching the same between a pairof block-resistant film layers, and the resulting sandwich is subjectedto heat and pressure to impress the textured surface of the substrate onthe film without blocking.

5. The process of claim 4, wherein the block-resistant film layers areconstituted of polyester sheets.

l =l l

1. A PROCESS FOR THE PREPARATION OF TRANSPARENCIES FOR USE INPHOTOREPRODUCTION, WHICH COMPRISES: A. PROVIDING A ROUGH, HIGHLYTEXTURED SUBSTRATE; APPLYING TO THE SUBSTRATE A SMOOTH NON-OLEFINICIMAGE CONSTITUTED FROM ONE OF THE GROUP CONSISTING OF FUSED XEROGRAPHICTONERS, PIGMENTS AND INKS; B. CONTACTING THE IMAGED SIDE OF SAIDSUBSTRATE WITH A POLYETHYLENE FILM; C. HEATING THE JUXTAPOSED IMAGE ANDFILM LAYERS TO A TEMPERATURE SUFFICIENT TO SOFTEN THE POLYETHYLENE FILMAND THEREBY FORM TEXTURED IMPRESSIONS OF THE NON-IMAGED AREAS OF SAIDSUBSTRATE THEREIN; D. COOLING THE JUXTAPOSED LAYERS TO FIX THE TEXTUREDIMPRESSIONS IN SAID FILM; AND E. STRIPPING THE THUS IMAGED POLYETHYLENEFILM FROM SAID SUBSTRATE TO FORM A FIXED TRANSPARENCY SUITABLE FORFURTHER USE IN PHOTOREPRODUCTION.
 2. The process of claim 1, wherein theoriginal image formed on said substrate is constituted on a copolymer ofa styrene-acrylic ester or polyacrylate-type xerographic toner.
 3. Theprocess of claim 1, wherein said substrate is paper.
 4. The process ofclaim 1, wherein said substrate and the polyethylene film layer areplaced in contact by sandwiching the same between a pair ofblock-resistant film layers, and the resulting sandwich is subjected toheat and pressure to impress the textured surface of the substrate onthe film without blocking.
 5. The process of claim 4, wherein theblock-resistant film layers are constituted of polyester sheets.